Heretofore, there have been many commercial articles made from prestressed concrete materials. These articles may include tubular pipes, beams, support columns, etc., and the concrete may include reinforcing rods, bars, and/or tubes therein. A large number of such prestressed concrete-metal reinforced articles have been made heretofore. Naturally, it is always desirable to make improved concrete products at reduced costs, or to obtain better physical properties in such products by novel production steps.
It is the general object of the present invention to provide an improved process for forming hollow prestressed concrete articles, such as poles, which have a metal outer shell.
Another object of the invention is to provide prestressed concrete columns, tubes, or poles positioned in metal enclosure tubes and which have desirable physical properties.
Another object of the invention is to provide an improved method for obtaining prestressed concrete poles which are made by substantially conventional apparatus and including using a corregated thin wall metal enclosure tube in forming the concrete poles.
The foregoing and other objects and advantages of the invention will be made more apparent as the specification proceeds.